In recent years, it has been focused attention on an organic electronic element such as an organic EL element or an organic solar cell. In these elements, a transparent electrode has became one of indispensable composing technologies.
Conventionally, as a transparent electrode, there has been mainly used an ITO transparent electrode having an indium-tin complex oxide (ITO) membrane produced by a vacuum deposition method or a sputtering process on transparent substrates, such as glass and a transparent plastic film. However, there were problems that a manufacturing cost was high since the metal oxide transparent conductive film manufactured using a vacuum processes, such as a vacuum deposition method and a sputtering process, was inferior with respect to manufacturing efficiency, and that it was inapplicable to the device application required to have a flexible nature since it was inferior with respect to flexibility.
Against this problem, it was proposed a method of forming a transparent conductive material layer by coating or printing using a coating liquid which is prepared by dissolving or dispersing a conductive polymer represented by π-conjugated polymer into a suitable solvent (for example, refer to Patent document 1). However, compared with a metal oxide transparent electrode prepared by a vacuum forming-film method, such as ITO, there was a problem that transparency and conductivity were decreased remarkably. Further, when an organic electronic device such as an organic EL element was formed using this, there was observed a behavior that the interface resistance with the functional layer prepared on this transparent conductive material layer was high (for example, increase of driving voltage for an organic EL element), in addition to low conductivity of a transparent electric conductive material layer itself. Namely, there was a problem of decreasing the performance as an element.
On the other hand, there was proposed a transparent conductive film produced by laminating a metal fine wire pattern and a conductive polymer (for example, refer to Patent document 2). However, when an organic EL element is formed using such a transparent conductive film, covering of the metal fine wire with the conductive was insufficient, and there was produced a current leak seemingly originated from the edge portion of the metal fine wire. This resulted in a problem of decreasing the performance of an element.
Regarding to the shape of these metal fine wires, several proposals were made in the filed of electromagnetic wave shield (for example, refer to Patent documents 3 and 4). However, these methods produced a shape having a high aspect ratio in the metal fine wire portion, and the height of the metal fine wire portion itself was very high. An organic electronic element targeted in the present application is produced by laminating many thin functional layers having a thickness of 1 μm or less on a transparent electrode. During the production, if the cross-sectional shape of the metal fine wire is a cone shape, or if the height of the metal fine wire is too high, film formation of the functional layers become difficult, and this will cause a large thickness distribution. This will cause decrease of element performance, and will produce the current leak as described above depending on the case, and it becomes difficult to form an element. Moreover, although it was disclosed a technology in which the electromagnetic wave shield pattern made of metal fine wires was covered with another solid conductive layer, it was not indicated about the covering state of the metal fine wire shape and a solid layer made of a conductive layer. Therefore, it is impossible to apply the metal fine wire pattern known in the filed of an electromagnetic wave shield to the transparent electrode used for an organic electronic element.